Method for forming improved liner layer and semiconductor device including the same

ABSTRACT

A method for manufacturing a semiconductor device includes conformally depositing a liner layer on a top surface of a dielectric layer, and on sidewall and bottom surfaces of an opening in the dielectric layer, annealing the liner layer, wherein the annealing is performed in at least one of a nitrogen (N 2 ) and ammonia (NH 3 ) ambient, at a temperature of about 60° C. to about 500° C., and at a power of about 200 Watts to about 4500 Watts, and forming a conductive layer on the liner layer on the top surface of the dielectric layer, and on the liner layer in a remaining portion of the opening.

TECHNICAL FIELD

The field generally relates to semiconductor devices and methods ofmanufacturing same and, in particular, to using an annealing process toform an improved liner layer.

BACKGROUND

Liner layers, such as, for example, titanium nitride (TiN), are used inthin film form in a variety of applications within semiconductortechnology. For example, a liner layer's ability as a diffusion barrieris important to mitigate oxygen ingress into complementary metal-oxidesemiconductor (CMOS) devices and to provide a consistent work functionfor uniform device operation. In addition, a liner layer, such astitanium nitride, is used as an effective diffusion barrier to preventmetals (such as copper, aluminum) from contaminating surroundingdielectric materials in back-end-of-line (BEOL), front-end-of-line(FEOL), and middle-of-line (MOL) metallization. As device dimensionscontinue to decrease, the ability to uniformly deposit a liner layer insmaller trenches with larger aspect ratios has required differentdeposition techniques other than physical based deposition. Thesedifferent deposition techniques result in increased levels ofcontamination in the liner layer thin films. The contamination isexacerbated by the need to deposit thinner films due to spatialrestrictions imposed by scaling for increased miniaturization.

SUMMARY

According to an exemplary embodiment of the present invention, a methodfor manufacturing a semiconductor device includes conformally depositinga liner layer on a top surface of a dielectric layer, and on sidewalland bottom surfaces of an opening in the dielectric layer, annealing theliner layer, wherein the annealing is performed in at least one of anitrogen (N₂) and ammonia (NH₃) ambient, at a temperature of about 60°C. to about 500° C., and at a power of about 200 Watts to about 4500Watts, and forming a conductive layer on the liner layer on the topsurface of the dielectric layer, and on the liner layer in a remainingportion of the opening.

According to an exemplary embodiment of the present invention, asemiconductor device includes a dielectric layer, an opening formed inthe dielectric layer, a liner layer on sidewall and bottom surfaces ofthe opening, and a conductive layer on the liner layer in the opening,wherein the liner layer comprises titanium nitride, and a density of theliner layer is greater than about 4.5 g/cm³.

According to an exemplary embodiment of the present invention, a methodfor manufacturing a semiconductor device includes forming a trench in adielectric layer, and forming a conductive structure in the trench,wherein forming the conductive structure comprises conformallydepositing a liner layer on sidewall and bottom surfaces of the trench,annealing the liner layer, wherein the annealing is performed in atleast one of a nitrogen (N₂) and ammonia (NH₃) ambient, at a temperatureof about 60° C. to about 500° C., and at a power of about 200 Watts toabout 4500 Watts, and forming a conductive layer on the liner layer inthe trench.

These and other exemplary embodiments of the invention will be describedin or become apparent from the following detailed description ofexemplary embodiments, which is to be read in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present invention will be described belowin more detail, with reference to the accompanying drawings, of which:

FIG. 1 is a cross-sectional view illustrating fabrication of asemiconductor device at a back-end-of-line (BEOL) or middle-of-line(MOL), and showing formation of openings in a dielectric, according toan exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating fabrication of asemiconductor device at a BEOL or MOL, and showing deposition of a linerlayer followed by an annealing process to modify the liner layer,according to an exemplary embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating fabrication of asemiconductor device at a BEOL or MOL, and showing metal deposition,according to an exemplary embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating fabrication of asemiconductor device at a BEOL or MOL, and showing planarization,according to an exemplary embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating fabrication of asemiconductor device at a front-end-of-line (FEOL), and showingformation of a gate dielectric, according to an exemplary embodiment ofthe present invention.

FIG. 6 is a cross-sectional view illustrating fabrication of asemiconductor device at a FEOL, and showing deposition of a liner layerfollowed by an annealing process to modify the liner layer, according toan exemplary embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating fabrication of asemiconductor device at a FEOL, and showing gate deposition, accordingto an exemplary embodiment of the present invention.

FIG. 8 is a cross-sectional view illustrating fabrication of asemiconductor device at a FEOL, and showing planarization, according toan exemplary embodiment of the present invention.

DETAILED DESCRIPTION

Exemplary embodiments of the invention will now be discussed in furtherdetail with regard to semiconductor devices and methods of manufacturingsame and, in particular, to using an annealing process to form animproved liner layer.

It is to be understood that the various layers and/or regions shown inthe accompanying drawings are not drawn to scale, and that one or morelayers and/or regions of a type commonly used in, for example,complementary metal-oxide semiconductor (CMOS), fin field-effecttransistor (FinFET), metal-oxide-semiconductor field-effect transistor(MOSFET) and/or other semiconductor devices may not be explicitly shownin a given drawing. This does not imply that the layers and/or regionsnot explicitly shown are omitted from the actual devices. In addition,certain elements may be left out of particular views for the sake ofclarity and/or simplicity when explanations are not necessarily focusedon the omitted elements. Moreover, the same or similar reference numbersused throughout the drawings are used to denote the same or similarfeatures, elements, or structures, and thus, a detailed explanation ofthe same or similar features, elements, or structures will not berepeated for each of the drawings.

The semiconductor devices and methods for forming same in accordancewith embodiments of the present invention can be employed inapplications, hardware, and/or electronic systems. Suitable hardware andsystems for implementing embodiments of the invention may include, butare not limited to, personal computers, communication networks,electronic commerce systems, portable communications devices (e.g., celland smart phones), solid-state media storage devices, functionalcircuitry, etc. Systems and hardware incorporating the semiconductordevices are contemplated embodiments of the invention. Given theteachings of embodiments of the invention provided herein, one ofordinary skill in the art will be able to contemplate otherimplementations and applications of embodiments of the invention.

The embodiments of the present invention can be used in connection withsemiconductor devices that may require, for example, CMOSs, MOSFETsand/or FinFETs. By way of non-limiting example, the semiconductordevices can include, but are not limited to CMOS, MOSFET and FinFETdevices, and/or semiconductor devices that use CMOS, MOSFET and/orFinFET technology.

As used herein, “height” refers to a vertical size of an element (e.g.,a layer, trench, hole, opening, etc.) in the cross-sectional viewsmeasured from a bottom surface to a top surface of the element, and/ormeasured with respect to a surface on which the element is located.Conversely, a “depth” refers to a vertical size of an element (e.g., alayer, trench, hole, opening, etc.) in the cross-sectional andthree-dimensional views measured from a top surface to a bottom surfaceof the element.

As used herein, “lateral,” “lateral side,” “lateral surface” refers to aside surface of an element (e.g., a layer, opening, etc.), such as aleft or right side surface in the drawings.

As used herein, “width” or “length” refers to a size of an element(e.g., a layer, trench, hole, opening, etc.) in the drawings measuredfrom a side surface to an opposite surface of the element.

As used herein, terms such as “upper”, “lower”, “right”, “left”,“vertical”, “horizontal”, “top”, “bottom”, and derivatives thereof shallrelate to the disclosed structures and methods, as oriented in thedrawing figures. For example, as used herein, “vertical” refers to adirection perpendicular to the top surface of the substrate in thecross-sectional views, and “horizontal” refers to a direction parallelto the top surface of the substrate in the cross-sectional views.

As used herein, unless otherwise specified, terms such as “on”,“overlying”, “atop”, “on top”, “positioned on” or “positioned atop” meanthat a first element is present on a second element, wherein interveningelements may be present between the first element and the secondelement. As used herein, unless otherwise specified, the term “directly”used in connection with the terms on”, “overlying”, “atop”, “on top”,“positioned on” or “positioned atop” or the term “direct contact” meanthat a first element and a second element are connected without anyintervening elements, such as, for example, intermediary conducting,insulating or semiconductor layers, present between the first elementand the second element.

According to an embodiment of the present invention, as devicedimensions continue to decrease, atomic layer deposition (ALD) orchemical vapor deposition (CVD) is used to uniformly deposit linerlayers, for example, titanium nitride, in smaller trenches with largeraspect ratios. ALD or CVD results in more conformal deposition, but alsogreater amounts of carbon impurities in the deposited film, and a lessdense film since carbon is a precursor for such processes. As filmthickness continues to decrease, these characteristics can lead to morevariation in the work function on the liner layer surface with adecreased ability to mitigate diffusion.

As a result, embodiments of the present invention utilize depositiontechniques for a liner layer such as, for example, ALD or CVD with theaddition of a plasma-based, annealing procedure that improves an initialdensity of the film and reduces the level of organic impurities withinthe film, such as, for example, carbon or carbon bonded with hydrogen,oxygen or nitrogen. According to embodiments of the present invention, amore consistent stoichiometry (e.g., ratio of titanium to nitrogen inthe case of a TiN film) is observed in the plasma-treated films, whichleads to a more uniform work function value when compared with filmsthat have not been subjected to the plasma-based, annealing procedure.

Accordingly, embodiments of the present invention create a denser andmore stable thin film for advanced metallization related applications inFEOL, MOL, and BEOL, where the liner material is deposited using, forexample, ALD or CVD techniques, and subjected to the disclosedplasma-based, annealing procedure. For example, in connection with FEOLgate metal related applications, embodiments of the present inventionresult in a dense and stable work function liner layer that preventsoxygen ingress from subsequent downstream fabrication in order toachieve stable device performance. For MOL contact related applications,embodiments of the present invention result in a dense and stable linerlayer, which can function as a sufficient fluorine or other halogenbarrier for subsequent contact processing, using, for example tungsten(W) or other materials deposited from fluorine-based or otherhalide-based precursors. In addition, a thickness of a dense and stableliner layer can be reduced, which may be critical for extendibility ofthe technology to smaller scale applications. In connection with BEOLcontact related applications, embodiments of the present inventionresult in a dense and stable liner layer, which can function as asufficient copper (Cu) diffusion barrier. For example, in order toimprove interconnect performance, increasing the Cu volume by reducingthe liner thickness can be critical.

Although embodiments of the present invention are discussed inconnection with a titanium nitride liner layer, the embodiments of thepresent invention are not necessarily limited thereto, and can beapplied with the same or similar results to thin film liner layerscomprising other materials, such as, for example, titanium, tantalum,tungsten, cobalt, ruthenium, iridium, nickel, rhodium and theirnitrides, oxides, silicides or other alloy materials.

In accordance with an embodiment of the present invention, a postdeposition annealing procedure includes a nitridation treatment thatremoves nitrogen containing, organic residue in a TiN liner layerdeposited by metalorganic atomic layer deposition (MOALD). As usedherein, “organic residue” refers to residue (e.g., remaining by-productsor contaminants) containing, for example, carbon, hydrocarbons (carbonsbonded with hydrogen), and/or carbon bonded with oxygen or nitrogen. Thepost deposition annealing procedure densifies the TiN, and can beperformed in, for example, a nitrogen (N₂) or ammonia (NH₃) ambient,using about 200 Watts (W) to about 4500 W power, for example, about 500W to about 2000 W. The power can be applied by high-frequency voltagewhich ionizes the ambient gas and creates a plasma. The annealing isperformed at a temperature of about 60° C. to about 500° C., forexample, at about 100° C. to about 250° C., for about 1 minute to about10 minutes, such as for example, about 2 minutes to about 5 minutes.

The post deposition annealing procedure reduces organic impurities,resulting in a high density TiN film, having a density that is greaterthan 4.5 g/cm³. The density of the film can be measured using, forexample, x-ray reflectivity (XRR). The reduction of the organicimpurities occurs due to the annealing process causing a reactionbetween ions in the plasma and organic impurities on a top surface ofthe film. The organic impurities include, for example, carbon,hydrocarbons, and carbon bonded with oxygen or nitrogen, and thereaction breaks the bonds in the organic impurities and volatizes theby-products.

FIG. 1 is a cross-sectional view illustrating fabrication of asemiconductor device at a back-end-of-line (BEOL) or middle-of-line(MOL), and showing formation of openings in a dielectric, according toan exemplary embodiment of the present invention. Referring to FIG. 1,one or more openings 107 (e.g., trenches) are formed in a dielectriclayer 105, such as, for example, silicon dioxide (SiO₂), carbon-dopedsilicon oxide (SiCOH), SiLK® dielectrics, and porous forms of theselow-k dielectric films. The trenches 107 can be defined using, forexample, lithography techniques, and then reactive ion etching (RIE) toopen the trenches 107. The trenches 107 can be formed through aplurality of dielectric layers 105.

According to an embodiment, the dielectric 105 and the trenches 107 arepart of a BEOL or MOL interconnect structure of an integrated circuitwhere the devices, including, but not limited to, transistors,capacitors, and resistors are interconnected with metallization layers(e.g., wiring) on a wafer. As can be understood by one of ordinary skillin the art, the dielectric layer 105 can be on a semiconductor substrate(not shown), with intervening layers between the dielectric layer 105and the substrate. A semiconductor substrate can be, for example, a bulksubstrate or a silicon-on-insulator (SOI) substrate including a buriedinsulating layer, such as, for example, a buried oxide or nitride layerlocated on an upper surface of the semiconductor substrate. Thesubstrate may comprise semiconductor material including, but not limitedto, Si, SiGe, SiC, SiGeC or other like semiconductor. In addition,multiple layers of the semiconductor materials can be used as thesemiconductor material of the substrate. A plurality of devices can beon the substrate, such as, for example, transistors, capacitors, andresistors.

FIG. 2 is a cross-sectional view illustrating fabrication of asemiconductor device at a BEOL or MOL, and showing deposition of a linerlayer followed by an annealing process to modify the liner layer,according to an exemplary embodiment of the present invention. Referringto FIG. 2, a liner layer 109 comprising, for example titanium nitride,or other liner material(s), is conformally formed on a top surface ofthe dielectric 105, and lining the sidewall and bottom surfaces of thetrenches 107. Deposition can be performed using, for example ALD. Otherdeposition processes, such as, for example, CVD or physical vapordeposition (PVD) may also be used. A thickness of the liner layer 109(e.g., height in the vertical direction and width in the horizontaldirection) can be, but is not necessarily limited to, about 5 angstromsto about 20 nm, for example, about 5 nm to about 10 nm.

As indicated by the arrows, following deposition of the liner layer 109,a plasma-based annealing procedure is performed on the liner layer 109at a temperature of about 60° C. to about 500° C., for example, at about100° C. to about 250° C., for about 1 minute to about 10 minutes, suchas for example, about 2 minutes to about 5 minutes in, for example, anitrogen (N₂) or ammonia (NH₃) ambient. The plasma-based annealingprocedure is performed using about 200 Watts (W) to about 4500 W ofpower, for example, about 500 W to about 2000 W.

FIG. 3 is a cross-sectional view illustrating fabrication of asemiconductor device at a BEOL or MOL, and showing metal deposition,according to an exemplary embodiment of the present invention. Referringto FIG. 3, after the annealing, an electrically conductive layer 110including, for example, nickel (Ni), cobalt (Co), iron (Fe), copper(Cu), gold (Au), silver (Ag), ruthenium (Ru), palladium (Pd), platinum(Pt), iridium (Ir), tungsten (W), and any mixtures or alloys thereof isdeposited on the liner layer 109 (e.g., titanium nitride thin film)using deposition techniques, including, but not necessarily limited to,PVD, CVD, ALD or sputtering. The conductive layer 110 fills in thetrenches 107 and is formed on the upper surface of the dielectric 105including the liner layer 109 to a height above the top surface of thedielectric 105. Alternatively, the conductive layer 110 may notnecessarily fill the entire trench 107, as in the case ofelectroplating, where a seed layer is deposited on the liner layer 109prior to electroplating to form the conductive layer 110.

FIG. 4 is a cross-sectional view illustrating fabrication of asemiconductor device at a BEOL or MOL, and showing planarization,according to an exemplary embodiment of the present invention. Referringto FIG. 4, the layers 109 and 110 on the top surface of the dielectric105 are polished off, using for example, a chemical mechanicalplanarization (CMP) process to planarize the top surface and result instructure shown in FIG. 4.

FIG. 5 is a cross-sectional view illustrating fabrication of asemiconductor device at a front-end-of-line (FEOL), and showingformation of a gate dielectric, according to an exemplary embodiment ofthe present invention. Referring to FIG. 5, a FEOL structure includes asubstrate 202, source/drain regions 203 and isolation regions 204, suchas shallow trench isolation (STI) regions in the substrate 202.

The substrate 202 can be, for example, a bulk semiconductor substrate ora silicon-on-insulator (SOI) substrate including a buried insulatinglayer, such as, for example, a buried oxide or nitride layer located onan upper surface of the semiconductor substrate. The substrate 202 maycomprise semiconductor material including, but not limited to, Si, SiGe,SiC, SiGeC or other like semiconductor. In addition, multiple layers ofthe semiconductor materials can be used as the semiconductor material ofthe substrate 202.

The isolation regions 204 can comprise dielectric material, including,but not limited to silicon dioxide (SiO₂), low-temperature oxide (LTO),high-temperature oxide (HTO), flowable oxide (FOX) or some otherdielectric.

A dielectric layer 205, including, for example, silicon dioxide (SiO₂),carbon-doped silicon oxide (SiCOH), SiLK® dielectrics, or porous formsof these low-k dielectric films is formed on the substrate 202. Gatespacers 208, comprising for example, a dielectric insulating materialincluding, but not necessarily limited to, silicon oxide, siliconnitride, silicon oxynitride, boron nitride, and/or silicon boronnitride, are formed in an opening in the dielectric layer 205. Thespacers 208 isolate the resulting gate from the source/drain regions203.

A gate dielectric 206 is formed between the spacers 208 corresponding toa channel region of a resulting gate. The gate dielectric 206 includes,for example, a high-K dielectric layer including, but not necessarilylimited to, HfO₂ (hafnium oxide), ZrO₂ (zirconium dioxide), hafniumzirconium oxide, A1 ₂O₃ (aluminum oxide), and Ta₂O₅ (tantalum pentoxide)or other electronic grade (EG) oxide. Examples of high-k materials alsoinclude, but are not limited to, metal oxides such as hafnium siliconoxynitride, lanthanum oxide, lanthanum aluminum oxide, zirconium oxide,zirconium silicon oxide, zirconium silicon oxynitride, tantalum oxide,titanium oxide, barium strontium titanium oxide, barium titanium oxide,strontium titanium oxide, yttrium oxide, aluminum oxide, lead scandiumtantalum oxide, and lead zinc niobate. The high-k material may furtherinclude dopants such as, for example, lanthanum and aluminum.

FIG. 6 is a cross-sectional view illustrating fabrication of asemiconductor device at a FEOL, and showing deposition of a liner layerfollowed by an annealing process to modify the liner layer, according toan exemplary embodiment of the present invention. Referring to FIG. 6, aliner layer 209 comprising, for example titanium nitride, or other linermaterial(s), is conformally formed on a top surface of the dielectric205, and on the gate spacers 208 and a top surface of the gatedielectric 206. Deposition can be performed using, for example ALD.Other deposition processes, such as, for example, CVD or physical vapordeposition (PVD) may also be used. A thickness of the liner layer 209(e.g., height in the vertical direction and width in the horizontaldirection) can be, but is not necessarily limited to, about 5 angstromsto about 20 nm, for example, about 5 nm to about 10 nm.

As indicated by the arrows, following deposition of the liner layer 209,a plasma-based annealing procedure is performed on the liner layer 209at a temperature of about 60° C. to about 500° C., for example, at about100° C. to about 250° C., for about 1 minute to about 10 minutes, suchas for example, about 2 minutes to about 5 minutes in, for example, anitrogen (N₂) or ammonia (NH₃) ambient. The plasma-based annealingprocedure is performed using about 200 Watts (W) to about 4500 W ofpower, for example, about 500 W to about 2000 W.

FIG. 7 is a cross-sectional view illustrating fabrication of asemiconductor device at a FEOL, and showing gate deposition, accordingto an exemplary embodiment of the present invention. Referring to FIG.7, after the annealing, an electrically conductive layer 210 (e.g., gatelayer) including, but not necessarily limited to, amorphous silicon(a-Si), or metals, such as, for example, tungsten, cobalt, zirconium,tantalum, titanium, aluminum, ruthenium, copper, metal carbides, metalnitrides, transition metal aluminides, tantalum carbide, titaniumcarbide, tantalum magnesium carbide, or combinations thereof isdeposited on the liner layer 209 (e.g., titanium nitride thin film)using deposition techniques, including, but not necessarily limited to,PVD, CVD, ALD or sputtering. The conductive layer 210 fills in the spacebetween the spacers 208 and conformal liner layer 209, and is formed onthe upper surface of the dielectric 205 including the liner layer 209 toa height above the top surface of the dielectric 205. Alternatively, theconductive layer 210 may not necessarily fill the entire space betweenthe spacers 208, as in the case of electroplating, where a seed layer isdeposited on the liner layer 209 prior to electroplating to form theconductive layer 210.

FIG. 8 is a cross-sectional view illustrating fabrication of asemiconductor device at a FEOL, and showing planarization, according toan exemplary embodiment of the present invention. Referring to FIG. 8,the layers 209 and 210 on the top surface of the dielectric 205 arepolished off, using for example, a chemical mechanical planarization(CMP) process to planarize the top surface and result in structure shownin FIG. 8. The gate dielectric 206, gate spacers 208, liner layer 209,and conductive layer 210 may be formed in a replacement metal gate (RMG)process.

The post deposition annealing procedure in accordance with embodimentsof the present invention, reduces organic impurities, resulting in ahigh density of the liner layer, for example, a density that is greaterthan 4.5 g/cm³ in the case of a TiN film. Density values may differ forother films including different materials. In addition, according toembodiments of the present invention, a more consistent stoichiometry(e.g., ratio of titanium to nitrogen in the case of a TiN film) isobserved in the plasma-treated films.

According to non-limiting embodiments of the present invention, surfacelayer thickness of a thin film liner layer is decreased, and the surfacelayer density of a thin film liner layer is increased after theplasma-based annealing procedure. In addition, in accordance withnon-limiting embodiments of the present invention, both the bulk layerthickness and density of a thin film liner layer are increased after theplasma-based annealing procedure.

It is to be understood that the results described in connection withplasma-based post deposition annealing described in accordance withembodiments of the present invention, can be applicable to each of theBEOL, FEOL or MOL configurations described herein.

Although illustrative embodiments of the present invention have beendescribed herein with reference to the accompanying drawings, it is tobe understood that the invention is not limited to those preciseembodiments, and that various other changes and modifications may bemade by one skilled in the art without departing from the scope orspirit of the invention.

We claim:
 1. A semiconductor device, comprising: a dielectric layer; anopening formed in the dielectric layer; a liner layer on sidewall andbottom surfaces of the opening; and a conductive layer on the linerlayer in the opening; wherein the liner layer comprises titaniumnitride, and a density of the liner layer is greater than about 4.5g/cm³.
 2. The semiconductor device according to claim 1, wherein theliner layer and the conductive layer form at least part of aninterconnect.
 3. The semiconductor device according to claim 1, whereinthe liner layer and the conductive layer form at least part of a gatestructure.
 4. The semiconductor device according to claim 3, wherein theliner layer is formed on a gate dielectric.
 5. The semiconductor deviceaccording to claim 3, wherein the liner layer is formed on a gatespacer.
 6. The semiconductor device according to claim 1, wherein athickness of the liner layer is in a range of about 5 angstroms to about20 nm.
 7. The semiconductor device according to claim 6, wherein athickness of the liner layer is in a range of about 5 nm to about 10 nm.8. The semiconductor device according to claim 1, wherein the linerlayer is an oxygen diffusion barrier.
 9. The semiconductor deviceaccording to claim 1, wherein the liner layer is a halogen diffusionbarrier.
 10. The semiconductor device according to claim 1, wherein theliner layer is a copper diffusion barrier.
 11. The semiconductor deviceaccording to claim 1, wherein the liner layer is an oxygen, halogen andcopper diffusion barrier.
 12. A semiconductor device, comprising: adielectric layer; an opening formed in the dielectric layer; a linerlayer conformally formed on a plurality of surfaces of the opening; anda conductive layer on the liner layer in the opening; wherein the linerlayer comprises titanium nitride, and a density of the liner layer isgreater than about 4.5 g/cm³.
 13. The semiconductor device according toclaim 12, wherein the liner layer and the conductive layer form at leastpart of an interconnect.
 14. The semiconductor device according to claim12, wherein the liner layer and the conductive layer form at least partof a gate structure.
 15. The semiconductor device according to claim 12,wherein a thickness of the liner layer is in a range of about 5angstroms to about 20 nm.
 16. The semiconductor device according toclaim 15, wherein a thickness of the liner layer is in a range of about5 nm to about 10 nm.
 17. The semiconductor device according to claim 12,wherein the liner layer is an oxygen diffusion barrier.
 18. Thesemiconductor device according to claim 12, wherein the liner layer is ahalogen diffusion barrier.
 19. The semiconductor device according toclaim 12, wherein the liner layer is a copper diffusion barrier.
 20. Thesemiconductor device according to claim 12, wherein the liner layer isan oxygen, halogen and copper diffusion barrier.